@w :100px;
@col : black;

div{
    width: @w;
    height: @w;
    background: @col;
    a{
        color: red;
        &:hover{
            color: green;
        }
    }
}

.font{
    font-size: 100px;
    color: red;
    display:inline-block;
    transition: 1s all ease;
    &:hover{
        color: blue;
        font-size: 300px;
        transform: rotate(100deg);
    }
}